To define and verify a backup and recovery strategy for the SAP systems:
· Establish and document a backup and recovery strategy for the SAP systems:
· Verify that the strategy is acceptable for the business requirements, including acceptable business limits on downtime for backups and restores or on amount of lost work
· Configure the backup tools, such as sapdba, brbackup, and the CCMS system after the strategy is defined, accepted, and documented
· Verify the data recovery procedures by restoring data saved to the backup medium
Objective of a backup strategy
A good backup strategy enables the DBA to restore any damaged file in a minimal amount of time, with minimal impact on the daily work.
The best backup strategy depends on the database, the available hardware, and the tools you choose. It also depends on the time windows available to make backups and if necessary to restore data.
A good strategy ensures that not only the database files but also the files at operating system level can be restored in case of failure.
You can have different plans for the different SAP systems in your landscape.
1. Create a plan to minimize database downtime. Downtime is time when the database cannot be used. Planned downtime is for normal database administration work. Unplanned downtime is for unforeseen events, such as a system or disk crash. Offline database backups require downtime. Online backups allow uninterrupted work with the database. Ask:
- How often can I afford to stop my database (once a day, once a week, once a month)?
- How long does a full offline backup take?
- What is the performance impact of an online backup?
- Can I schedule backups without interaction of an operator (at night)?
- On what media do I want to store my backup (tape, disk, CD)?
- What backup tools are available for my database?
- How long will a restore of the entire database take?
- How long will a restore of parts of the database, such as a tablespace, take?
- What is my backup cycle, that is, how long do I keep tapes before re-using them?
After answering these questions, decide what downtime you can afford. The decision also depends on whether your system is for development or production.
If your production system must be available 24 x 7, consider using high availability tools that are provided by certified hardware partners or external companies.
For more information on this topic, see the SAP Knowledge Product SAPDBA for your database version.
2. Find appropriate tools for the strategy and estimate the costs.
- In view of your hardware, database, and requirements, decide on the tool you want to use to back up the database.
- If your database is Oracle or Informix, you can use the SAP tools sapdba, brbackup, and brarchive to back up the database and the logfiles.
3. Define a person responsible for performing the backups.
- It is essential that this is one responsible person. This person must be aware of the impact backups have on the availability of the system, and of the importance in case of a disk crash, or worse scenarios.
- Name another person as a substitute, in case the primary person is not available. The substitute must be familiar with the responsibilities and database tools.
4. Verify the results from the backup. Ensure that the data stored on the backup medium is readable and that the medium contains the data expected.
- For example, the tools for backup from SAP have an option to verify the data that was written to tape during the backup. Regularly verify data written to the backup medium.
- Do not rely on the results in the logfile of the backup. Check the data on the backup medium. Check that it can be read from the medium. When a backup is made to tape, check the quality of the backup.
- Some tools for backups let you verify the result of the backup. For example, BRBACKUP and BRARCHIVE can be run with the option ‘-v’ to read the data written to tape and compare it with data on the disk. These options extend the time for the backup but must be used regularly, for example, every four weeks.
5. Verify your backup strategy by performing a recovery. As an exercise, perform a disaster recovery of some data from the backup medium. The most likely disaster requiring recovery of a database is the failure of a disk. Take precautions to ensure that the exercise does not become a new disaster:
- Never delete a file to simulate the failure of a disk. Move a file to another location.
- Do not use files of the database that contain data. Use files that contain indexes. To restore the file, use only data that was verified on the backup medium.
- Make sure you have enough logfiles in case you need to take an older backup.
- Restore the files from the backup medium (for example, tape) to the disk.
- For a detailed description of how to perform a test of a disaster recovery, see the SAP Knowledge Product SAPDBA.
Use the following SAP tools to help you carry out database administration tasks:
· sapdba
· brbackup
· brarchive
· brrestore
You are not required to use these tools, but they have some advantages:
· They can be scheduled from CCMS within the system.
· They communicate with the CCMS alert system.
· You can back up operating system files in the same way as database files.
· SAP Support is familiar and confident with them.
Backup and recovery plan that shows:
· How and when to make backups of your database and system
· What types of data recovery tests have been performed
Assignment of one or more persons who:
· Are responsible for scheduling and performing backups
· Know what to do in case of problems or failures
Test backup and recovery procedures often to become familiar with different situations and reduce stress in an actual data loss situation.
· If possible, practice on a test system, or on a system that has SAP installed, before it is needed by the project team.
· Refer to the section Database Interface, Database Platforms (BC-DB) in the SAP online help documentation.
· For detailed information and instructions, refer to the appropriate sections in the guide System Administration Made Easy.